Children and adults undergoing thoracic surgeries often require unilateral lung ventilation and/or anesthesia. Specially designed endotracheal tube setups are used by anesthesiologists to facilitate unilateral ventilation procedures. Multiple endotracheal tube systems are currently in use that are specifically designed to either intubate the mainstem bronchus of the ventilated lung or to block the mainstem bronchus of the non-ventilated lung. However, each of these tube designs has specific limitations.
The tubes designed to intubate the mainstem bronchus of the ventilated lung include two fixed channels within the tube. When the procedure is completed and the patient is restored to bilateral ventilation, the presence of the two fixed channels undesirably limits airflow in and out of the lung by increasing resistance, thus adversely altering the mechanics. Therefore it is desirable to re-intubate the patient with a standard endotracheal tube following completion of the surgical procedure utilizing unilateral lung ventilation. However, repeated intubations are known to result in trauma to the epithelial lining of the airways.
It is also known to use a standard endotracheal tube to perform unilateral lung ventilation by passing a balloon catheter through a standard endotracheal tube such that the balloon catheter is inserted into the bronchus of the lung to be blocked. The balloon is subsequently inflated. The catheter contains a single lumen for access to the non-ventilated lung. This use of the balloon catheter with the standard endotracheal tube eliminates the need for re-intubation of the patient associated with the use of tubes specifically adapted to intubate the mainstem bronchus of a lung. However, the passage of the balloon catheter through the standard endotracheal tube places the catheter within the main lumen of the standard tube, thereby disrupting laminar airflow in the main lumen. Also, the balloon catheter can move around within the main lumen because it is not constrained with respect to the main lumen. This movement of the catheter contributes to the need for periodic repositioning of the balloon in the blocked bronchus, which can be a source of trauma to the epithelial tissues. Furthermore, the catheter accessing the non-ventilated lung is not thermally isolated from the main orifice of the endotracheal tube, which can be a limitation for a potential therapy to be described herein.
During unilateral lung ventilation procedures, the unventilated lung is collapsed and sometimes manually moved from the surgical field. Resulting contusions, alveolar collapse and atelectasis are known to contribute to lung inflammation. Moreover, it is difficult to maintain arterial oxygen saturation because of the extreme ventilation/perfusion (V/Q) mismatch that results when one lung receives no ventilation. In an effort to maintain blood oxygen levels when there is such dramatic V/Q mismatch, elevated inspired oxygen levels are supplied to the ventilated lung. Such high oxygen levels, however, are known contributors to lung disease. Laboratory studies indicate that lung function is hampered following re-recruitment of a collapsed lung after only 30 minutes of unilateral lung ventilation. The studies also demonstrate that unilateral lung ventilation using conventional techniques has a dramatic impact on lung morphology.
What is needed is a ventilation technique aimed at attenuating or eliminating the alterations in lung function and inflammation noted when bilateral ventilation is restored following a unilateral ventilation procedure. More particularly, what is needed is a device and method for unilateral lung ventilation that provides for delivery of therapeutic agents and/or interventions to both the ventilated and the non-ventilated lung before, during and following the procedure. The focus is to optimize V/Q matching during the unilateral ventilation procedure and to treat the lung for the inflammatory response to the associated traumas.